Topographic Analysis of Calcite (104) Cleavage Surface Dissolution in Ethanol–Water Solutions

Shaoxiong Ye,Pan Feng,Jiaping Liu

doi:10.3390/min11040376

Abstract

The interaction of organic molecules with calcite surfaces plays a key role in many geochemical, industrial and biomineralization processes, and exploring the influences of organic molecules on calcite reactions is crucial for a fundamental understanding of the reaction mechanisms. Here, we used digital hologram microscopy to explore the in situ evolution of the calcite (104) surfaces when dissolved in ethanol–water solutions, and total organic carbon analysis was applied to confirm the adsorption of ethanol by calcite. The results showed that the bulk dissolution rate of calcite decreases as the volume fraction of ethanol increases, and the topographic features of etch pits were also altered by the presence of ethanol. When exposed to too much ethanol, the etch pits’ growth was inhibited and their shapes tended to change from rhombuses in ultrapure water to triangles. Our results provide insights into the interaction between adsorbed ethanol and evolving calcite crystal, which highlights the dissolution regulation of calcite by organic molecules that could benefit a broad range of fields.

Highlights

Jiangsu Key Laboratory of Construction Materials, School of Materials Science and Engineering, State Key laboratory of High Performance Civil Engineering Materials, Nanjing 210008, China
This paper monitors the dissolution behaviors of calcite at (104) cleavage surfaces submerged in flowing ethanol–water solutions, and the results show that ethanol inhibited calcite dissolution and altered the topographic features of the etch pits
Crystals intended for the dissolution rate measurements were imaged by the digital hologram microscopy (DHM) equipped with a 20× immersion objective lens, which is able to monitor a regional surface of approximately 194 μm × 194 μm with a lateral resolution of 299 nm, while crystals intended for the investigation of the ethanol effect on the etch pits’ growth were first stored in a 20% ethanol–water solution for 12 h and were exposed to flowing solutions and imaged by the DHM equipped

Summary

Introduction

Jiangsu Key Laboratory of Construction Materials, School of Materials Science and Engineering, State Key laboratory of High Performance Civil Engineering Materials, Nanjing 210008, China. The interaction of organic molecules with calcite surfaces plays a key role in many geochemical, industrial and biomineralization processes, and exploring the influences of organic molecules on calcite reactions is crucial for a fundamental understanding of the reaction mechanisms. Our results provide insights into the interaction between adsorbed ethanol and evolving calcite crystal, which highlights the dissolution regulation of calcite by organic molecules that could benefit a broad range of fields. A better understanding of the regulation of organic molecules on calcite surface reactions, including dissolution and growth, would help to unravel the mechanisms of biomineralization and benefit a broad range of fields, such as biomimetic material design [5], nanoengineering [6] and environmental sustainability [7]. A few studies have investigated how several types of organic molecules

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